Li Yang, Chen Jian, Tang Shuheng, Xi Zhaodong
School of Earth and Environment, Anhui University of Science and Technology, Huainan 232001, China.
The Key Laboratory of Universities in Anhui Province for Prevention of Mine Geological Disasters, Anhui University of Science and Technology, Huainan 232001, China.
Microorganisms. 2023 Jun 25;11(7):1657. doi: 10.3390/microorganisms11071657.
The rise of coalbed methane bioengineering enables the conversion and utilization of carbon dioxide through microbial action and the carbon cycle. The environment of underground coal reservoirs is the result of a comprehensive effort by microorganisms. Some studies on reservoir microorganisms have progressed in laboratory conditions. However, it does not replicate the interaction between microorganisms and the environment on site. Hydraulic fracturing is an engineering technology to improve the natural permeability of tight reservoirs and is also a prerequisite for increasing biomethane production. In addition to expanding the pore and fracture systems of coal reservoirs, hydraulic fracturing also improves the living conditions of microbial communities in underground space. The characteristics of microbial communities in the reservoir after hydraulic fracturing are unclear. To this end, we applied the 16S rRNA sequencing technique to coalbed methane production water after hydraulic fracturing south of the Qinshui Basin to analyze the microbial response of the hydraulic fracturing process in the coal reservoir. The diversity of microbial communities associated with organic degradation was improved after hydraulic fracturing in the coal reservoir. The proportion of Actinobacteria in the reservoir water of the study area increased significantly, and the abundance of Aminicenantes and Planctomycetes increased, which do not exist in non-fracturing coalbed methane wells or exist at very low abundance. There are different types of methanogens in the study area, especially in fracturing wells. Ecological factors also determine the metabolic pathway of methanogens in coal seams. After hydraulic fracturing, the impact on the reservoir's microbial communities remains within months. Hydraulic fracturing can strengthen the carbon circulation process, thereby enhancing the block's methane and carbon dioxide circulation. The study provides a unique theoretical basis for microbially enhanced coalbed methane.
煤层气生物工程的兴起使得通过微生物作用和碳循环实现二氧化碳的转化与利用成为可能。地下煤储层环境是微生物综合作用的结果。一些关于储层微生物的研究在实验室条件下取得了进展。然而，它无法复制现场微生物与环境之间的相互作用。水力压裂是一种提高致密储层天然渗透率的工程技术，也是增加生物甲烷产量的前提条件。除了扩大煤储层的孔隙和裂缝系统外，水力压裂还改善了地下空间中微生物群落的生存条件。水力压裂后储层中微生物群落的特征尚不清楚。为此，我们将16S rRNA测序技术应用于沁水盆地南部水力压裂后的煤层气产出水中，以分析煤储层水力压裂过程中的微生物响应。煤储层水力压裂后，与有机降解相关的微生物群落多样性得到改善。研究区域储层水中放线菌的比例显著增加，氨基聚糖菌和浮霉菌的丰度增加，这些在未压裂的煤层气井中不存在或丰度极低。研究区域存在不同类型的产甲烷菌，尤其是在压裂井中。生态因素也决定了煤层中产甲烷菌的代谢途径。水力压裂后，对储层微生物群落的影响在数月内仍然存在。水力压裂可以加强碳循环过程，从而增强区块的甲烷和二氧化碳循环。该研究为微生物强化煤层气提供了独特的理论基础。
